Absolute parametric instabilities of a nonuniform magnetized plasma
A theory is derived for the absolute parametric instabilities which are excited in a nonuniform magnetized plasma by electromagnetic radiation at a frequency comparable to the electron plasma frequency. The thresholds and growth rates are determined for the aperiodic instability, for the decay into a lower-hybrid wave and an ion-acoustic wave, and for the decay into two lower-hybrid waves, depending on the nature of the pump wave. Under certain conditions, the nonuniformity of the plasma density does not affect the threshold for the absolute parametric instabilities. The size of the plasma region in which the parametric turbulence arises is comparable to the characteristic dimension of the density gradient. The efficiency with which microwave power is parametrically absorbed as a result of the onset of absolute instabilities is evaluated. It is concluded that these instabilities can cause a significant absorption of millimeter-range microwave power under the conditions expected in future large tokamaks.
- Research Organization:
- P. N. Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow
- OSTI ID:
- 6691482
- Journal Information:
- Sov. J. Plasma Phys. (Engl. Transl.); (United States), Journal Name: Sov. J. Plasma Phys. (Engl. Transl.); (United States) Vol. 6:3; ISSN SJPPD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700107* -- Fusion Energy-- Plasma Research-- Instabilities
ABSOLUTE INSTABILITIES
CLOSED PLASMA DEVICES
DECAY INSTABILITY
ELECTROMAGNETIC RADIATION
HEATING
HIGH-FREQUENCY HEATING
HYBRID RESONANCE
INHOMOGENEOUS PLASMA
INSTABILITY
MICROWAVE RADIATION
PARAMETRIC INSTABILITIES
PLASMA
PLASMA DENSITY
PLASMA HEATING
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RADIATIONS
RESONANCE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES